Thanks for the input guys.

Let's go for a requirement to use explicit non numeric field bridges for faceted fields and relax that requirement when the new faceting comes up

Ok. I already updates the tests there and switching to non numeric bridges works fine. I'll need to add something to the docs still.

Treating documentId as special and thus non numeric field is fine by me ...

Ok. In fact I already was able to cover the embedded it the same way. So embedded ids would be string encoded as well.

The idea of extracting the list of terms of a query and check if such a term is a NumericField and raise an alarm is a good idea and it looks like it could be done in it's specific and minimal form relatively quickly.

Right, I am also looking for minimal validation to start with. I think it is doable. I give it a go.